CORAL SPRINGS, Fla. - A cellphone video is now at the center of a fatal Coral Springs road-rage investigation.

As loved ones prepare for a memorial service for Paul Peterman, 37, investigators continue to piece together what happened between the two drivers.

Paul Peterman was found unconscious near his pickup truck after Thursday morning's rush-hour altercation with Joshua Tullis

Tullis, a Broward Sheriffs' Office firefighter, began recording the incident on his phone, captured the moment when Peterman, a deaf man from Margate, dove through the passenger window of Tullis' truck.

A struggle is then heard inside the vehicle before Tullis, sped away.

Meanwhile, Peterman is unconscious, lying on the road.

He later died at a hospital. The cause of Peterman’s death remains unknown.

Peterson's loved ones said they are heartbroken about the incident, and are determined to figure out what happened before the confrontation was caught on camera.

"It's a senseless death that we don't understand, " Peterman's mother, Bernie Peterman, said. "The loss of your son is just heart wrenching. There's just no words that people can say but we know he's with God in heaven."

Schwartzreich said Tullis feels awful about what happened, but he feared for his life and had no idea what happened to Peterman until he saw it on the news.